"Stationary" Newtrons are by far the most common. They typically cling to rocky walls, invisible, until Sonic gets close. Then the sneaky machines de-cloak just long enough to fire an energy ball in the hedgehog's direction, before fading back into the background. Once vanished, Newtrons cannot be destroyed even if Sonic spin attacks where you know they are hiding; if they're invisible, the chance for points is lost.

"Rocket" Newtrons are seen in only one Zone, the original 16-bit Green Hill. Like their green counterparts, they remain invisible until Sonic walks close by, but instead of firing an energy bolt they drop off the wall and transform into a ground-skimming missile! Given that the badniks persist in this form - rather than turning invisible again later - they are much easier to destroy than the stationary Newtrons.

Confusion may arise when Newtrons are referred to as "Green" or "Blue". In 16-bit Green Hill Zone - this being the most well-known deployment of Newtrons - the stationary form was green/grey while the rocket form was blue/red. However, in Sonic the Hedgehog (8-bit), the stationary ("Green") Newtron came in neutral grey, while in Sonic the Hedgehog 2 (8-bit) the stationary Newtron was actually blue! In Sonic 4 a lime-green Newtron has the ability to fire an energy ball while stationary and transform into a rocket.